Method of forming electronic package having fluid-conducting channel

ABSTRACT

To accommodate high power densities associated with high-performance integrated circuits, an integrated circuit (IC) package includes a heat-dissipating structure in which heat is dissipated from a surface of one or more dice to a heat spreader. The heat spreader has a fluid-conducting channel formed therein, and a fluid coolant may be circulated through the channel via a micropump. In an embodiment, the channel is located at or near a surface of the heat spreader, and a heat-generating IC is in thermal contact with the heat spreader. In an embodiment, the IC is a thinned die that is coupled to the heat spreader via a thinned thermal interface material. Methods of fabrication, as well as application of the package to an electronic assembly and to an electronic system, are also described.

DIVISIONAL APPLICATION

The present application is a divisional of U.S. patent application Ser.No. 10/404,310, filed on Mar. 31, 2003, now issued as U.S. Pat. No.7,126,822, which is incorporated herein by reference.

RELATED APPLICATIONS

This application is related to the following applications, which areassigned to the same assignee as the present application:

(1) Ser. No. 10/036,389, entitled “Thinned Die Integrated CircuitPackage”, now issued as U.S. Pat. No. 6,841,413.

(2) Ser. No. 10/956,621, entitled “Die Exhibiting an EffectiveCoefficient of Thermal Expansion Equivalent to a Substrate MountedThereon, and Processes of Making Same”.

TECHNICAL FIELD

The subject matter relates generally to electronics packaging and, moreparticularly, to an electronics package with fluid cooling, and tomethods related thereto.

BACKGROUND INFORMATION

An integrated circuit (“IC”) die may be assembled into an IC package.One or more IC packages may be physically and electrically coupled toanother packaging element, such as a printed circuit board (“PCB”)and/or a heat spreader to form an “electronic assembly”. The “electronicassembly” may be part of an “electronic system”. An “electronic system”is broadly defined herein as any product comprising an “electronicassembly”. Examples of electronic systems include computers (e.g.,server, router, desktop, laptop, hand-held, Web appliance, etc.),wireless communications devices (e.g., cellular phone, cordless phone,pager, computer with wireless network, etc.), computer-relatedperipherals (e.g., printer, scanner, monitor, wireless network card,etc.), entertainment devices (e.g., television, radio, stereo, tape andcompact disc players, video cassette recorder, camcorder, digitalcamera, MP3 (Motion Picture Experts Group, Audio Layer 3) player, etc.),and the like.

In the field of electronic systems there is competitive pressure amongmanufacturers to drive the performance of their equipment up whiledriving down production costs. This is particularly true regarding thepackaging of IC's, where each new generation of packaging may provideincreased performance, particularly in terms of an increased number ofcomponents and higher clock frequencies, while generally being smalleror more compact in size. As the internal circuitry of IC's, such asprocessors, operates at higher and higher clock frequencies, and as IC'soperate at higher and higher power levels, the amount of heat generatedby such IC's may increase their operating temperature to unacceptablelevels. However, the performance and reliability of IC's may diminish asthe temperature to which they are subjected increases, so it becomesincreasingly important to adequately dissipate heat from ICenvironments, including IC packages.

For the reasons stated above, and for other reasons stated below whichwill become apparent to those skilled in the art upon reading andunderstanding the present specification, there is a significant need inthe art for apparatus and methods for packaging an IC that minimize heatdissipation problems associated with high clock frequencies and highpower densities.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an electronic system incorporating at leastone electronic assembly with fluid cooling, in accordance with anembodiment of the subject matter;

FIG. 2 illustrates a side representation and a partially schematicrepresentation of an electronic assembly comprising an IC package havingfluid cooling, in accordance with an embodiment of the subject matter;

FIG. 3 illustrates a top representation of a heat spreader having aserpentine fluid-conducting channel therein, in accordance with anembodiment of the subject matter;

FIG. 4 illustrates a side, exploded representation of an IC packagecomprising a heat spreader with a fluid-conducting channel therein, inaccordance with an embodiment of the subject matter;

FIG. 5 illustrates a side, exploded representation of an IC packagecomprising a heat spreader with a fluid-conducting channel therein, inaccordance with an embodiment of the subject matter;

FIG. 6 illustrates a side, exploded representation of an IC packagecomprising a heat spreader with a fluid-conducting channel therein, inaccordance with an embodiment of the subject matter;

FIGS. 7, 8, 9, and 10 together illustrate a method of fabricating an ICpackage comprising a heat spreader with a fluid-conducting channeltherein, in accordance with an embodiment of the subject matter;

FIG. 11 is a flow diagram of several methods of fabricating an ICpackage comprising a heat spreader with a fluid-conducting channeltherein, in accordance with various embodiments of the subject matter;and

FIG. 12 is a flow diagram of a method of fabricating a heat spreaderwith a fluid-conducting channel therein, in accordance with anembodiment of the subject matter.

DETAILED DESCRIPTION

In the following detailed description of embodiments of the subjectmatter, reference is made to the accompanying drawings that form a parthereof, and in which is shown by way of illustration specific preferredembodiments in which the subject matter may be practiced. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the subject matter, and it is to be understoodthat other embodiments may be utilized and that structural, mechanical,compositional, electrical, and procedural changes may be made withoutdeparting from the spirit and scope of the subject matter. The followingdetailed description is, therefore, not to be taken in a limiting sense,and the scope of the subject matter is defined only by the appendedclaims.

The subject matter provides a solution to thermal dissipation problemsthat may be associated with prior art packaging of IC's that have highcircuit density and that operate at high clock speeds and high powerlevels, by employing a high capacity heat spreader in thermal contactwith one or more IC's. Various embodiments are illustrated and describedherein.

In an embodiment, a back surface of an IC die may be coupled to a heatspreader having a fluid-conducting channel formed therein. A fluidcoolant may be circulated through the channel via a suitable pump, suchas a micropump. In an embodiment, the channel is located at or near asurface of the heat spreader. In another embodiment the channel islocated within the heat spreader and away from its outer surfaces. In anembodiment, the IC is a thinned die that is coupled to the heat spreadervia a thinned thermal interface material. Methods of fabrication, aswell as application of the package to an electronic assembly and to anelectronic system, are also described.

FIG. 1 is a block diagram of an electronic system 100 incorporating atleast one electronic assembly 102 with fluid cooling, in accordance withan embodiment of the subject matter. Electronic system 100 is merely oneexample of an electronic system in which the subject matter may be used.In this example, electronic system 100 comprises a data processingsystem that includes a system bus 118 to couple various components ofthe system. System bus 118 provides communications links among variouscomponents of the electronic system 100 and may be implemented as asingle bus, as a combination of busses, or in any other suitable manner.

“Suitable”, as used herein, means having characteristics that aresufficient to produce the desired result(s). Suitability for theintended purpose can be determined by one of ordinary skill in the artusing only routine experimentation.

Electronic assembly 102 is coupled to system bus 118. Electronicassembly 102 may include any circuit or combination of circuits. In anembodiment, electronic assembly 102 includes a processor 104 which maybe of any type. As used herein, “processor” means any type ofcomputational circuit, such as but not limited to a microprocessor, amicrocontroller, a complex instruction set computing (CISC)microprocessor, a reduced instruction set computing (RISC)microprocessor, a very long instruction word (VLIW) microprocessor, agraphics processor, a digital signal processor (DSP), or any other typeof processor or processing circuit.

Other types of circuits that may be included in electronic assembly 102are a custom circuit, an application-specific integrated circuit (ASIC),or the like, such as, for example, one or more circuits (such as acommunications circuit 106) for use in wireless devices like cellulartelephones, pagers, portable computers, personal digital assistants,two-way radios, and similar electronic systems. The IC may perform anyother type of function.

Electronic system 100 may also include an external memory 110, which inturn may include one or more memory elements suitable to the particularapplication, such as a main memory 112 in the form of random accessmemory (RAM), one or more hard drives 114, and/or one or more drivesthat handle removable media 116 such as floppy diskettes, compact disks(CDs), digital video disks (DVD), and the like. In an embodiment, mainmemory 112 comprises dynamic random access memory IC's. In otherembodiments, flash memory IC's, static RAM IC's, and the like could beused in main memory 112.

Electronic system 100 may also include a display device 108, one or morespeakers 109, and a keyboard and/or controller 120, which may include amouse, trackball, game controller, voice-recognition device, or anyother device that may permit a system user to input information into andreceive information from the electronic system 100.

FIG. 2 illustrates a side representation and a partially schematicrepresentation of an electronic assembly 200 comprising an IC package202 having fluid cooling, in accordance with an embodiment of thesubject matter.

In the example shown in FIG. 2, an electronic assembly 200 comprises anIC package 202. IC package 202 may comprise a die 205 coupled to a heatspreader 220 via a thermal interface material 206. In an embodiment, die205 may comprise a processor; in another embodiment the die may comprisea different kind of heat-generating component, such as an ASIC,amplifier, and the like. In an embodiment, one or more heat-generatingdiscrete components, such as a resistor, capacitor, inductor, and thelike, may be substituted for die 205. In an embodiment, multiple dicemay be coupled to heat spreader 220.

Heat spreader 220 may comprise a fluid-conducting channel 212 formedtherein. Heat spreader 220 may have a thickness in the range ofapproximately 1.5-6 mm. In an embodiment, heat spreader 220 may have athickness of approximately 3 mm.

In an embodiment, a suitable fluid is circulated through channel 212 bya pump, such as micropump 230. The fluid may move in the directionindicated by arrows 218. The output side of micropump 230 may be coupledvia supply pipe 222 and intake pipe 214 to channel 212 of heat spreader220. An outlet pipe 224 and a removal pipe 216 may couple channel 212 tothe intake side of micropump 230. In FIG. 2, micropump 230, supply pipe222, and removal pipe 216 are illustrated schematically, and they may bephysically located in any suitable place, either inside or outside theIC package 202.

In an embodiment, a micropump 234 may be formed as part of the heatspreader 220 and/or integrated into it. Micropump 234 may serve in placeof or in addition to micropump 230.

Micropumps 230 and 234 may be of any suitable type. For example,micropumps 230 and 234 may be of the membrane-displacement type, such aspiezoelectric, electrostatic, thermopneumatic, electromagnetic,photothermal, and the like. They may also be field-induced flow pumps,such as electrokinetic, electroosmotic, electrohydrodynamic,magnetohydrodynamic, and the like. Alternatively, any suitablemechanical pump, such as but not limited to an impeller, rotary,reciprocating, or screw pump, may be used.

The fluid circulating through channel 212 may be of any suitable type,such as deionized water or acetonitrile. Either a one-phase system or atwo-phase system may be utilized. In a one-phase system, the fluid mayremain essentially a liquid as it travels through the system. In atwo-phase system, a two-phase fluid partially changes into a vapor as itmoves through a portion of the system, and it changes back to a liquidas it moves through another portion of the system. In an example of atwo-phase embodiment, an incoming liquid may become partially vaporizedas a two-phase fluid as it passes through channel 212 and absorbs heatfrom the die 205, and the fluid may condense back to a liquid as itpasses through a condenser or heat exchanger 232 or is otherwise cooled.

In an embodiment, micropump 230 and/or micropump 234 are electrokineticpumps. In general, micropumps of the types mentioned above, includingelectrokinetic pumps, may offer the advantages of having relativelysimple architecture, no moving parts, low power consumption, andrelatively high reliability.

Micropump 230 and/or micropump 234 may be fabricated in any suitable wayand from any suitable material. For example, they may be micro-machinedusing known Micro Electro Mechanical Systems (“MEMS”) techniques. Theymay be fabricated from silicon. As mentioned above, micropump 234 may befabricated within heat spreader 220.

In an embodiment, multiple micropumps may be provided for electronicassembly 200, and they may be operated in series or in parallel. Ifdesired, a suitable heat exchanger 232 may be coupled into the fluidcooling system to further dissipate heat.

Heat spreader 220 may comprise any suitable material, such as copper,copper alloys including copper alloys with tungsten, copper laminates,molybdenum, molybdenum laminates, molybdenum alloys, aluminum, aluminumalloys including metallized aluminum nitride, beryllium oxide, diamond,ceramic, and the like.

In the example shown in FIG. 2, a thinned die 205 may be used. Die 205may have a thickness, for example, in the range of 20-300 μm. In anembodiment, die 205 has a thickness not exceeding 100 μm.

In the example shown in FIG. 2, a thinned thermal interface material 206may be used. Thermal interface material 206 may have a thickness, forexample, in the range of 1 to 100 μm. In an embodiment, thermalinterface material 206 has a thickness of approximately 6 μm.

Thermal interface material 206 may comprise any suitable material, suchas lead, nickel, vanadium, tin, indium, gallium, bismuth, cadmium, zinc,copper, gold, silver, antimony, germanium, and alloys thereof. In anembodiment, thermal interface material 206 comprises an alloy ofapproximately 80% gold, 20% tin, and a trace amount of nickel (e.g. lessthan 1%). In an embodiment, thermal interface material 206 comprises ahard solder having a melting temperature above 280 degrees Centigradeand a tensile strength of exceeding 40,000 pounds per square inch.However, in other embodiments, a different minimum melting temperatureand tensile strength could be selected. For example, in an embodiment,the thermal interface material 206 may comprise material having atensile strength exceeding 4,000 pounds per square inch.

The above-referenced “Related Applications” disclose various embodimentsof component packaging utilizing thinned dies and thinned thermalinterface materials. IC packages based upon the inventive concepts inthe “Related Applications” may have significant advantages in terms ofease of fabrication, yield, and reliability, and they may also provide areduced thermal resistance between heat-generating areas andheat-dissipating areas of the packages.

In the example shown in FIG. 2, the die 205, to which the heat spreader220 is coupled, does not overlap or underlie the entire channel 212.That is, the die 205 has a geometry of a first size; the channel 212 hasa geometry of a second size; and the second size is greater than thefirst size. In this example, a core element 210 may be used to overlapthe portion of the channel 212 that is not overlapped by the die 205. Inthis example, the core element 210 is shown laterally adjacent to thedie 205. The core element 210 may be formed of any suitable material,such as a plastic, a metal, a ceramic, and the like. The core element210 may assist in covering, sealing, protecting, and/or stiffening theportion of channel 212 that is not overlapped by die 205. Channel 212may otherwise lack adequate sealing, protection, and stiffening, becausethe thermal interface material 206 may be very thin, as mentioned above.

FIG. 3 illustrates a top representation of a heat spreader 300 having aserpentine fluid-conducting channel 302 therein, in accordance with anembodiment of the subject matter. Channel 302 may comprise an inlet area304 and an outlet area 306 to couple to corresponding pipes, hoses,supply channels, and the like.

In this example, channel 302 makes a serpentine path from a first sideof heat spreader 300, e.g. the right-hand side as shown in FIG. 3, to asecond side of heat spreader 300, e.g. the left-hand side of FIG. 3.

Any other suitable geometry for channel 302 may be used, including butnot limited to a plurality of parallel channels, one or more chambers,and/or any combination of channel geometries. In general, the channelgeometry may be selected to provide relatively more heat transfer fromthose portions of the die that generate relatively more heat than otherportions of the die.

The cross-section of channel 302 may be of any suitable geometry. In anembodiment, channel 302 has a square cross-section of approximately 50μm per side. The width of channel may be in the range of 20 to 1000 μm.

FIG. 4 illustrates a side, exploded representation of an IC package 400comprising a heat spreader 420 with a fluid-conducting channel 412therein, in accordance with an embodiment of the subject matter. ICpackage 400 may be similar to, identical to, or different from ICpackage 202 shown in FIG. 2.

IC package 400 comprises a heat spreader 420 with a fluid-conductingchannel 412, which may be of a serpentine geometry, and which may becoupled between an inlet chamber 414 and an outlet chamber 424. In thisembodiment, channel 412 is formed in a bottom surface (as viewed in FIG.4) of heat spreader 420.

IC package 400 further comprises a thermal interface material 406, whichmay be thinned, as mentioned earlier. In addition, IC package 400comprises die 405, which may also be thinned. Further, one or more coreelements 410 may be provided to cover the portions of channel 412 and ofthermal interface material 406 that are not covered by die 405. In anembodiment, core element 410 may comprise a single O-shaped element thatsurrounds die 405; however, in other embodiments, core element 410 maycomprise other geometries, such as strips, L-shaped segments, one ormore C-shaped segments, and the like.

FIG. 5 illustrates a side, exploded representation of an IC package 500comprising a heat spreader 520 with a fluid-conducting channel 512therein, in accordance with an embodiment of the subject matter.

IC package 500 comprises a heat spreader 520 with a fluid-conductingchannel 512, which may be of a serpentine geometry, and which may becoupled between an inlet chamber 514 and an outlet chamber 524. In thisembodiment, channel 512 is formed within the interior of heat spreader520, i.e. relatively distant from the top and bottom surfaces of heatspreader 520. One of ordinary skill in the art may determine withoutundue experimentation suitable locations for channel 512 within theinterior of heat spreader 520.

IC package 500 further comprises a thermal interface material 506, whichmay be thinned, as mentioned earlier. In addition, IC package 500comprises die 505, which may also be thinned. In this embodiment, itwill be noted that core elements, such as core element(s) 410 (refer toFIG. 4), are unnecessary, because the die overlaps substantially theentire thermal interface material 506.

FIG. 6 illustrates a side, exploded representation of an IC package 600comprising a heat spreader 620 with a fluid-conducting channel 612therein, in accordance with an embodiment of the subject matter.

IC package 600 comprises a heat spreader 620 with a fluid-conductingchannel 612, which may be of a serpentine geometry, and which may becoupled between an inlet chamber 614 and an outlet chamber 624. In thisembodiment, channel 612 is formed at or very near the bottom surface ofheat spreader 620.

IC package 600 further comprises a thermal interface material 606, whichmay be thinned, as mentioned earlier. In addition, IC package 600comprises die 605, which may also be thinned.

In this embodiment, it will be noted that the width of die 605 is lessthan that of heat spreader 620. Also, the width of the area occupied bychannel 612 is less than that of die 605. The width of thermal interface606 may be the same as that of heat spreader 620, or it could bedifferent from that of heat spreader 620, e.g. the same width as that ofdie 605. Core elements, such as core element(s) 410 (refer to FIG. 4),may be unnecessary, because the die overlaps substantially the entirewidth of the area occupied by channel 612; however, one or more coreelements could be used in this embodiment, if desired.

FIGS. 7, 8, 9, and 10 together illustrate a method of fabricating an ICpackage comprising a heat spreader 700 with a fluid-conducting channel702 therein, in accordance with an embodiment of the subject matter.

FIG. 7 illustrates a side view of a heat spreader 700 formed of anysuitable material, such as those mentioned earlier. In an embodiment,heat spreader 700 is formed of copper.

Channel 702 may be fabricated in any suitable manner, e.g. bymicro-machining, punching, etching, scribing, drilling, and the like. Inan embodiment, a plurality of grooves may be formed in the bottomsurface of heat spreader 700. In addition, an inlet via or chamber 704and an outlet via or chamber 706 may be formed in heat spreader 700.

FIG. 8 illustrates a side view of heat spreader 700 following theapplication of a filler material 708 to the channel 702 and to the inletand outlet chambers 704 and 706, respectively. Filler material 708 maybe applied and polished to assist in preparing a suitable bondingsurface on the bottom surface of heat spreader 700. Filler material 708may comprise a material that can be dissolved at relatively lowtemperature using a suitable solvent. In an embodiment, filler material708 may comprise a photoresist material. In another embodiment fillermaterial 708 may comprise a wax that is soluble in water and/or acetone.

FIG. 9 illustrates a side view of heat spreader 700 following attachmentof a thermal interface material 712 to the bottom surface. Alsoillustrated in FIG. 9 are die 705 and core element(s) 710, which havebeen attached to thermal interface material 712. Filler material 708still remains within channel 702 and within the inlet and outletchambers 704 and 706, respectively.

Thermal interface material 712 may be formed on the bottom surface ofheat spreader 700. In an embodiment, the bottom surface of heat spreader700 may have a layer of Ni formed on it through any suitable technique.A layer of Au may be formed over the layer of Ni, and a layer of Sn maybe formed over the layer of Ni.

Prior to attachment of die 705 to thermal interface material 712, theback side of die 705 may be suitably coated with one or more layers ofmetal, as necessary, to promote adhesion, to provide a diffusionbarrier, to inhibit oxidation, and so forth. For adhesion, Ti or TiN maybe used. For a diffusion barrier, Ni or NiV may be used. To inhibitoxidation, Au, Pt, or Ag may be used. In an embodiment, die 705 may havea layer of Ni, followed by a layer of Au.

To couple die 705 to heat spreader 700, die 705 and heat spreader 700are subjected to a suitable amount of heat to cause the thermalinterface material 712 to melt. In an embodiment wherein the thermalinterface material 712 comprises Au, Ni, and Sn, and the die 705comprises a layer of Au over a layer of Ni, the Au may begin diffusinginto the Sn around 230 C. Within the range of approximately 280-310 Cthe Ni may diffuse into the Au/Sn alloy. In this embodiment, the Au/Snalloy may be approximately 80% Au and 20% Sn by weight, and it maycontain a trace amount of inter-diffused Ni at the interface between thedie 705 and the thermal interface material 712, as well as at theinterface between the thermal interface material 712 and the heatspreader 700. In other embodiments, different materials may besubstituted for those described.

FIG. 10 illustrates a side view of heat spreader 700 after fillermaterial 708 has been removed from channel 702 and from the inlet andoutlet chambers 704 and 706, respectively. In addition, an inlet pipe718 has been inserted into inlet chamber 704, and an outlet pipe 714 hasbeen inserted into outlet chamber 706. Inlet pipe 718 and outlet pipe714 may or may not be necessary, depending upon how channel 702 iscoupled to a suitable pump (not illustrated in FIG. 10).

FIG. 11 is a flow diagram of several methods of fabricating an ICpackage comprising a heat spreader with a fluid-conducting channeltherein, in accordance with various embodiments of the subject matter.The methods start at 1100.

In 1102, a fluid-conducting channel is formed in an element of an ICpackage that is to be coupled to a surface of one or moreheat-generating components, such as one or more semiconductor dice. Thepackage element may comprise a heat spreader. The heat spreader maycomprise material selected from the group consisting of copper, copperalloys including copper alloys with tungsten, copper laminates,molybdenum, molybdenum laminates, molybdenum alloys, aluminum, aluminumalloys including metallized aluminum nitride, beryllium oxide, diamond,and ceramic.

The heat-generating component may be a die. The die may comprise aprocessor or other heat-generating IC. The die may be a thinned die. Inan embodiment, the die may have a thickness in the range of 50 to 150μm; in an embodiment the die has a thickness not exceeding 100 μm.

The channel may make a serpentine path from a first side of the heatspreader to a second side of the heat spreader. The channel may beformed in the interior of the heat-spreading element or on or near asurface of the element.

In an embodiment, the die may overlap the entire channel. In anembodiment, the die may not overlap the entire channel, and at least onecore element may overlap a portion of the channel that is not overlappedby the die. The core element(s) may comprise a material selected fromthe group consisting of a plastic, a metal, and a ceramic.

In 1104, a thermal interface material is coupled to the heat-spreadingelement. In an embodiment, the thermal interface material may bethinned. In an embodiment, the thermal interface material may have athickness in the range of 5 to 20 μm.

In 1106, the die is coupled to the thermal interface material. Themethods end at 1108.

FIG. 12 is a flow diagram of a method of fabricating a heat spreaderwith a fluid-conducting channel therein, in accordance with anembodiment of the subject matter. The methods start at 1200.

In 1202, a channel is formed in a surface of a heat spreader. Thechannel may be formed in any suitable manner, including any techniquedescribed herein.

In 1204, the channel is filled with a suitable filler material.

In 1206, the surface is polished.

In 1208, the die is attached to the surface of the heat spreader. Thedie may be attached using a thermal interface material. In anembodiment, a thinned die and a thinned thermal interface material areused.

In 1210, a core may optionally be attached to the surface, if desired.

In 1212, the filler material is removed. The methods end at 1214.

The operations described above with respect to the methods illustratedin FIGS. 11 and 12 may be performed in a different order from thosedescribed herein. Although the flow diagrams of FIGS. 11 and 12 show an“End”, they may be performed continuously if desired.

The above-described choice of dice, pump(s), thermal interface material,heat spreader material, core material, type of fluid, geometry,dimensions, fabrication operations, and assembly sequencing may all bevaried by one of ordinary skill in the art to optimize the yield,reliability, and performance characteristics of the package.

The resulting package is flexible in terms of the orientation, size,number, order, and composition of its constituent elements. Variousembodiments of the subject matter may be implemented using variouscombinations of pump and heat spreader technologies, choice ofmaterials, and fabrication operations, to achieve the advantages of theinventive subject matter. The structure, including types of materialsused, dimensions, layout, geometry, and so forth, of the package may bebuilt in a wide variety of embodiments and fabrication methods,depending upon the requirements of the electronic assembly or electronicsystem of which it forms a part.

FIGS. 1-10 are merely representational and are not drawn to scale.Certain proportions thereof may be exaggerated, while others may beminimized. FIGS. 1-12 are intended to illustrate various embodiments ofthe subject matter that can be understood and appropriately carried outby those of ordinary skill in the art.

The inventive subject matter provides for an electronic assembly andmethods of manufacture thereof that minimize thermal dissipationproblems associated with high power delivery. An electronic systemand/or data processing system that incorporates one or more electronicassemblies that utilize the subject matter can handle the relativelyhigh power densities associated with high performance integratedcircuits, and such systems may therefore be more commerciallyattractive.

By substantially increasing the thermal dissipation from highperformance electronic assemblies, such electronic equipment may beoperated at increased clock frequencies. Alternatively, such equipmentmay be operated at reduced clock frequencies but with lower operatingtemperatures for increased reliability.

As shown herein, the subject matter may be implemented in a number ofdifferent embodiments, including an integrated circuit package, anelectronic assembly, an electronic system in the form of a dataprocessing system, and various methods of fabricating an IC package andan electronic assembly. Other embodiments will be readily apparent tothose of ordinary skill in the art after reading this disclosure. Theelements, materials, geometries, dimensions, and sequence of operationsmay all be varied to suit particular packaging requirements.

While certain operations have been described herein relative to “upper”and “lower” surfaces, it will be understood that these descriptors arerelative, and that they would be reversed if the IC package orelectronic assembly were inverted. Therefore, these terms are notintended to be limiting.

The concepts of the subject matter may be applied to any type of ICpackage or electronic assembly.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement that is calculated to achieve the same purpose maybe substituted for the specific embodiment shown. This application isintended to cover any adaptations or variations of the subject matter.Therefore, it is manifestly intended that embodiments of the subjectmatter be limited only by the claims and the equivalents thereof.

It is emphasized that the Abstract is provided to comply with 37 C.F.R.§ 1.72(b) requiring an Abstract that will allow the reader to ascertainthe nature and gist of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims.

In the foregoing Detailed Description, various features are occasionallygrouped together in a single embodiment for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments of the subjectmatter require more features than are expressly recited in each claim.Rather, as the following claims reflect, inventive subject matter liesin less than all features of a single disclosed embodiment. Thus thefollowing claims are hereby incorporated into the Detailed Description,with each claim standing on its own as a separate preferred embodiment.

1. A method comprising: forming a fluid-conducting channel in a packageelement of an integrated circuit package to couple to an upper surfaceof a die, wherein the die has a geometry of a first size, wherein thechannel has a geometry of a second size greater than the first size;forming at least one O-shaped core element to overlap a portion of thechannel not overlapped by the die, wherein the core element is laterallyadjacent to and surrounds the die, and wherein the core element has anupper surface co-extensive with the upper surface of the die and coupledto the package element; coupling a thin thermal interface material tothe package element; coupling the die to the thin thermal interfacematerial; wherein forming the fluid-conducting channel includes: formingthe channel in a surface of the package element; filling the channelwith a filler material; after filling, polishing the surface of thepackage element; and after coupling the die to the thermal interfacematerial, removing the filler material.
 2. The method recited in claim 1wherein, in forming the fluid-conducting channel, the package elementcomprises a heat spreader.
 3. The method recited in claim 2 wherein, informing the fluid-conducting channel, the heat spreader comprisesmaterial selected from the group consisting of copper, copper alloysincluding copper alloys with tungsten, copper laminates, molybdenum,molybdenum laminates, molybdenum alloys, aluminum, aluminum alloysincluding metallized aluminum nitride, beryllium oxide, diamond, andceramic.
 4. The method recited in claim 1 wherein, in forming thefluid-conducting channel, the die to which the package element is to becoupled comprises a processor.
 5. The method recited in claim 1 wherein,in forming the fluid-conducting channel, the channel makes a serpentinepath from a first side of the package element to a second side of thepackage element.
 6. The method recited in claim 1 and furthercomprising: forming a pump, coupled to the channel, in the packageelement.
 7. The method recited in claim 1 wherein, in forming the atleast one core element, the core element comprises material selectedfrom the group consisting of a plastic, a metal, and a ceramic.
 8. Themethod recited in claim 1 wherein, in forming the fluid-conductingchannel, the die to which the package element is to be coupled has athickness not exceeding 100 μm.
 9. The method recited in claim 1,wherein the filler comprises a photoresist material or wax.
 10. A methodcomprising: forming a fluid-conducting channel in a heat spreader of anintegrated circuit package to couple to an upper surface of a die,wherein the die has a geometry of a first size, wherein the channel hasa geometry of a second size greater than the first size; using a thermalinterface material to couple the upper surface of the die to a surfaceof the heat spreader; and forming at least one O-shaped core element tooverlap a portion of the channel not overlapped by the die, wherein thecore element is laterally adjacent to and surrounds the die, and whereinthe core element has an upper surface co-extensive with the uppersurface of the die and coupled to the heat spreader; wherein forming thefluid-conducting channel includes: forming the channel in a surface ofthe heat spreader; filling the channel with a filler material; afterfilling, polishing the surface of the heat spreader; and after couplingthe die to the heat spreader, removing the filler material.
 11. Themethod recited in claim 10 wherein, in using the thermal interfacematerial, the die to which the heat spreader is coupled comprises aprocessor.
 12. The method recited in claim 10 wherein, in forming thefluid-conducting channel, the channel makes a serpentine path from afirst side of the heat spreader to a second side of the heat spreader.13. The method recited in claim 10, wherein the filler comprises aphotoresist material or wax.
 14. A method comprising: forming afluid-conducting channel in the interior of a heat spreader of a thinnedintegrated circuit package to couple to an upper surface of a die,wherein the die has a geometry of a first size, wherein the channel hasa geometry of a second size greater than the first size; using a thinnedthermal interface material to couple the upper surface of the diedirectly to a surface of the heat spreader; and forming at least onecore element to overlap a portion of the channel not overlapped by thedie, wherein the core element is laterally adjacent to and surrounds thedie, and wherein the core element has an upper surface co-extensive withthe upper surface of the die and coupled to the heat spreader; whereinforming the fluid-conducting channel includes: forming the channel neara surface of the heat spreader; filling the channel with a fillermaterial; after filling, polishing the surface of the heat spreader; andafter coupling the die to the thermal interface material, removing thefiller material.
 15. The method recited in claim 14 wherein, in formingthe at least one core element, the at least one core element comprisesmaterial selected from the group consisting of a plastic, a metal, and aceramic.
 16. The method recited in claim 14 wherein, in forming the atleast one core element, the core element is O-shaped and surrounds thedie.
 17. The method recited in claim 14 wherein, in forming the at leastone core element, the core element comprises at least one L-shapedelement or at least one C-shaped element.
 18. The method recited inclaim 14 wherein, in forming the at least one core element, the coreelement comprises at least one strip.
 19. The method recited in claim 14and further comprising: forming a pump, coupled to the channel, in theheat spreader.
 20. The method recited in claim 14, wherein the fillercomprises a photoresist material or wax.